This paper presents an analytical investigation of the non-linear behaviour of
coupled concrete walls using unbonded post-tensioned precast concrete coupling
beams under monotonic lateral loading. Coupling of the walls is achieved by
post-tensioning the beams and walls together at the floor and roof levels. Steel
top and seat angles are used at the beam-to-wall interfaces and are designed to
yield and provide energy dissipation during an earthquake. As the structure is
laterally displaced, the non-linear deformations occur primarily as a result of the
opening of gaps at the beam-to-wall interfaces. This system offers many
advantages over monolithic cast-in-place beams such as simpler detailing, the
ability to undergo large lateral displacement with little damage to the structure,
and self-centring capabilities. To assess how the system behaviour can be
controlled by design, structural parameters such as the beam and wall geometry,
the amount of post-tensioning, and the top and seat angle properties are varied.
The effect of these parameters on the lateral strength and deformation capacities
and demands are investigated through non-linear pushover analyses. Results
demonstrate that this innovative system can provide excellent stiffness, strength,
and ductility in a properly designed multi-story structure.
Keywords: concrete, coupled walls, post-tensioning, seismic analysis, precast
concrete.